A high sodium ion level in plasma and other extracellular body fluids, is a problem frequently found in patients undergoing treatment with diuretics for elevated blood pressure. Patients with high sodium ion levels, typically also have low potassium ion levels. Accordingly, a pharmaceutical composition that provides for the exchange of potassium ion for sodium ion, advantageously treats both abnormalities. Unlike conventional potassium supplements such as a potassium chloride elixir, this type of pharmaceutical composition has the further advantage of not increasing the total ionic load of sodium and potassium.
In other patients, a high potassium ion level in the body fluids, is a problem. Sodium polystyrene sulfonate ion exchange resin is often administered to reduce potassium ion levels in these hyperkalemic patients. The resin is not bioabsorbable. Typically, the resin is given orally, but may be administered rectally.
Four years ago, sales of calcium supplements totaled $47 million. Now, the figure is closer to $200 million a year, as the public has responded to the 1984 NIH recommendation of 1000 mg a day to prevent osteoporosis. Postmenopausal women, particularly thin, white women, are most at risk. A drawback of certain calcium supplements is a lack of bioavailability of the calcium.
As illustrated by U.S. Pat. No. 4,395,392 to Wolgemuth, oral administration of a certain water-soluble vinylbenzenesulfonic acid polymer, decreases urinary calcium content.
As exemplified by U.S. Pat. No. 4,542,015 to Smakman et al, the phosphate level in the blood of a patient requiring dialysis, may be reduced by using in the clearance department of a dialysis apparatus, a cation exchanger charged with ferric ions and alkali metal ions. In place of ferric ions, ions of thorium, tin, lanthanum, aluminum or zirconium metal may be used. In a preferred embodiment, the cation exchanger is also charged with alkaline earth metals. In one embodiment, the charged cation exchanger may be orally administered in capsule form.
As described by U.S. Pat. No. 2,611,730 to Heming, a high sodium ion level in body fluids may be reduced by the oral administration of a cation exchange resin, and it has been observed that the use of resins has resulted in depleted blood levels of calcium and potassium. Heming's detailed description shows cation exchangers having a loading of calcium within the normal electrolyte range. Furthermore, Heming's exemplary resins are charged with a physiologically insignificant cation or with an amino acid, said to be physiologically insignificant.
I have surprisingly discovered that an alkali metal cation-charged, cation exchange resin having a loading of an alkaline earth metal within the normal electrolyte range, will seriously deplete alkaline earth metal cations from body fluids. Therefore, there is a need for an alkali metal cation-charged, cation exchange resin that prevents serious depletion of calcium and magnesium cations from body fluids. There is an even greater need for a resin of this type that maintains the calcium and magnesium values within the normal electrolyte ranges.
If charged with potassium, such a cation exchanger would exchange potassium for sodium, and therefore be useful for reducing the body level of sodium and increasing the potassium level. If charged with sodium, such a cation exchange resin would exchange sodium for potassium, and accordingly be useful for reducing the body level of potassium. Thus, the discovery of such an alkali metal cation-charged, cation exchanger would constitute a significant contribution to the medical art. Such a cation exchanger would contribute even further to the medical art if it also had utility in treating hypocalcemic patients.